Thread-cutting mechanism for sewing-machines.



A. RONTKE.

THREAD CUTTING MECHANISM FOR SEWING MACHINES. APPLICATION FILEDAUG-2.1912.

1,156,821. Patented Oct. 12, 1915.

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WITNESSES: l/Vl/E/VTOR (.Zl ZEmt/m 4%, 3 404011, a?" or A TTOB/VEYCOLUMBIA PLANGGRAPH c0.. WASHINGTON, n.

A. RONTKE.

THREAD CUTTING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED AUG-2, 1912.

1,156,821. Patented 0ct.12,1915.

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WITNESSES: l/Il I/EA/ TOR A TTOR/VE I COLUMBIA PLANOGRAPH co.,WASHINGTON, D. c.

ALBERT RONTKE, or Bn'InGEronr,oouNEczrrcuT, nssieivortrornn SINGER'MANUQFAGTURING COMPANY, A oonronnrio v or NEW'JERSEY. v

1 THREAD-CUTTING MECHANISM Fon-sEwING-Miecirmns.

To all whom it may concern:

7 Be it known that I, ALBnR'r RoN'rKn, a citizenvof the United States,1'esiding, at Bridgeport, in thecounty of Fairfield and State ofConnecticut, have invented certain 7 new and useful Improvements inThread- Cutting Mechanism for Sewing-Machines,

of-which the following is a specification, reference being had thereinto the accompanying drawings.

This invention relates to improvements in sewing machines for closingthe mouths of filled bags, and has for its object to provide 1 improvedmeans for severing the thread between the successive stitchingoperations, to which end there is provided a cylinder bed sewing machinehaving its needle-carrying bar arranged to operate in a substantiallyhorizontal plane and provided with a thread-cutter.normally located atone side of the vertical plane intersecting the line of seam formation,thus effecting a construction convenient of manipulation and par- .ofclosing the ends ticularly adapted to meet the requirements ofcomparatively small sized packages. f p

In the accompanying drawings illustrat-.. ing the invention, in theseveral figures of which like parts are similarly designated, Figure 1is a rear side view of a sewing machine together with the improvedthreadcutting mechanism shown as attached to the cylinder bed-plate, themachine being ar-z ranged to cause theneedle-bar to be actu- -v1ded wltha guiding element OI PlIl, as 27, which tracks one of the openings28formedated in a substantially horizontal plane. Fig. 2 is an end view ofthe cylinder bedplate and thread-cutting mechanism, together with aportion of the presser-foot Fig. 3 is a front side view of a portion ofthe cylinder bed-plate and thread-cutting mechanism, together withdotted line views of a stitched bag and a partially stitched bag. Fig. 4is adetail view of the threadcutting mechanism. Fig. 5 is a detail viewof the shear blades.

The invention is shown as applied to a Singer 54: class machine, but asit relates only to the construction and application of thethread-cutting mechanism, only such reference will. be made to the otherelements of the machine as is deemed necessary for a Specificationofrtte rs Patent. t t 0 1;, 1'2, 1915, Applicationfiled'August2,1912 Seria1 No, 712,843. v if v carriedby one form of looper-actuating vshaft(not, shown), 5 the needle-carry jug-bar, 6 the Icloth-presser carryingbar pro? 7 vided with thecloth-presser 7, 8 the needle, 9 the throat orneedle plate, 10 the feed-dog, [and 11 the upper portion of a-verticallyarranged standard, to which. the sewingjmachineis secured by nutbolts,as l2. 13 represents the cutter base-plate secured by screws, as 14:,Ytothe cylinder bed-plate,

abell crank operating lever which is provided with an integrally formedhub 16 and pivotally mounted on said cutter base-plate by a stud screw17 threaded into said plate.

.18 and19vrepresent coacting shear blades constructed w1th guide arms 20and 21 each arranged'at an angle to its respective shear blade, saidblades being pivotally mounted on a nut bolt 22 carried by the arm 23 ofi the operating lever 15 and yieldingly held in cutting relationship byspring 24 surrounding the nut bolt 22, which latter is I free to bemoved in the direction of its length in the hub 16. The free end. of the.arm 25 of said bell crank operating lever is connected withcommon meansto advance the shear blades into position to sever the thread, as shownin Fig. 4, a spring 26 secured at one end to said bell crank lever andhaving its opposite end secured to the cylinder bed-plate acting to holdsaid cutting blades in their normal positions, as shown in Figs.'1,2 and3.

Each of the guide arms 20 and21 prolati'onship with the sewing thread.

Claims a 7 1. In a sewing machine, the-combination with a bed-plate, ofa thread-cuttingmechanism normally located at one side of the line 1 Iof seam formation,isaid cutting mechanism comprising a cutteractuatinglever pro- 1 vicled with pivotally attached cutting blades resilientlyheld in cutting relationship and movable across the line of seamformation, each of said blades being provided with'a' guide arm, ofstationaryguiding elements in effective relationwith said guide arms toimpart shearing movements.

- of seam formation, said cutting mechanism comprising a cutterbase-plate secured to said bed-plate, a cutter-actuating lever pivotallymounted on said base-plate and pro vided With pivotally attached cuttingblades resiliently held in cutting relationship, each of said bladesbeing provided With a guide arm in effective relationship with saidbaseplate to impart shearing movements to said blades as the latter aremoved across the 1-5 line of seam formation.

In testimony whereof, I have signed my name to this specification; inthe presence of tWo subscribing Witnesses.

ALBERT RONTKE.

Witnesses JAMEs J .Cox, ABBIE MpDoNnmn.

Copies of this patent may be obtainedfor five: cents each, byaddressing" the Commissioner of Paten Y Y WashingtomD. 01" r

